Thermostatic overload switch



Feb; 8,1938. H, J. HAMMERLY vRe. 20,

. THEHMOSTATIC OVERLOAD SWITCH Original Filed Dec. 24, 1934 2 Sheets-Sheef 1 2 4s 37 33 4 42 O 19 16 INVYENTOR I 12 HERMQN J HAMMERLY,

Feb. 8, 1938. H. J. HAMMERLY 20,649

THERMOSTATIC OVERLOAD SWITCH Original Filed Dec. 24, 1934 I 2 Sheets-Sheet 2 Reissued Feb. 8, 1 93s THERMOSTATIC OVERLOAD SWITCH Herman J. Hammcrly, New Britain, Conn, assignor to The Trumbull Electric Manufacturin: Company, Plainville, Conn. a corporation of. Connecticut Original No. 2,038,105. IIIMADI'II 21, 1936. Serial No. 758,913. December 24, 1934. Application for reissue November 2, 1937, Serial No. 172,467

21 Claims. (Cl. 200-116) My invention relates particularly to electric switches adapted to be normally manually actuated but which will automatically open the circuit in case of an overload.

One object is to provide an extremely-simple and practical construction of the snap action toggle type which is automatically released by the action of a thermostatic strip to open the circuit in case of an overload. The switch is nor- The operating lever 2| carries a metal 0- shaped member with hinge pins 22 which are pivotally supported in the bearing openings 23 in the side arms 24 of the bracket or frame of which the front plate I! is a part.

The toggle link II has hinge members 26 pivoted in the openings 21 inthe inner ends of the arms 24 The end 28 0! the toggle member 25 has a hinge-like connection in ,the end of the slotted bar I! which loosely slides in the handle mally actuated to off and on positions by the sim- II in the usual manner. The swinging move pie tilting o1 a finger lever. A bimetallic thermomerit of' the lever 25 is limited by the projection static strip in the form of a latch holds the parts 30 which extends into the slot 3| in one of the when they are moved to the closed circuit posiarms '2 of the frame. The spring 32 is' mounted tion. A removable and renewable heater unit on the slotted bar 2! and p against the coacts with the thermostatic strip to release-the washer I! so as to snap the lever 25- back 15 toggle action in case of an overload. The switch and forth as the huge! piece II is actuated. may then be reset manually as soon as the ther- The bimetallic thermostatic latch member 33 mostatic strip cools oil. is supported by the post 34. The fl pp r member The exact form of embodiment is not vital to l! is hinged in the lugs 36 which form a part of go the invention. the toggle member 25. One end 31 of the member Fig. 1 shows a front view of one form of con- I! is adapted to coact with the hook oi the latch struction embodying my invention. It and act as a catch and the otherend' 3! .co-

Fig. 2 shows a vertical section and side elevaacts with thecross bar III of the movable switch tion with the parts in the oil or open circuit member to act like a cam to tone the switch '5 position. member to a closed circuit or on position. The

Fig. 3 is a rear view. cross piece 3! serves as an abutment or stop for Fig. 4 is a transverse sectional view on the theilnger part II of the member 35. plane oi the line 4-4 .01 Fig. 1 The action of the switch under normal load Fig. 5 is a vertical sectional view on a some-' conditions is very much the same as that oi. a

a what dlflerent plane from that of Fig. 2 but also conventional type toggle switch. In other words. showing the parts in the open circuit or oil posiwhen the switch is oi! or in the open circuit tion and omitting the box part of the housing. position of Fig. 5 the circuit may be closed by Fig. 6 is a smilar sectional view showing the simply lifting the finger piece 2i suillciently so parts in the on or closed circuit position. that the cross piece 2' of the toggle link 25 a Fig. '1 is a fragmentary view showing the parts comes below the center linewhereupouthe toggle in the position which they occupy when released action closes the circuit. The opening of the t o t cally. p circuit is eflected by moving the finger piece 2] Fig. 8 is an exploded perspective view showing in the reverse direction whereupon the snap acparts of the switch mechanism. tion of the toggle takes placeaided by the spring a The switch shown is of the enclosed snap action action of the arms I! and II. 4 type. The housing is madeup oi the base or The resistance or heater unit I! maybe formed iront section II and the box like portion ll both from a flat stamping or flattened wire-formed formed of insulating material and held together into a coil or zigzag shape and secured-in place by a number oi screws II which screw into the by screws II and 4!. The screw II .is threaded face plate II. The binding post or terminal it into one end oi the bracket 43 which is connected is electrically connected to the spring switch to the terminal I'I. Thescrew flisthreaded into arm II. the movable end of which coacts with the the bracket 44 which has the circuit terminal stationary contact I. l! at the front. The plate of mica or other The terminal i1 is electrically connected to suitable insulating materialisinterposed between the spring switch arm II, the movable end of the heater orresistanceunit and the thermostatic u I which is adapted to engage the stationary co'nlatch ll.

tact II. A screw ll may be. provided for adjusting the These two arms II and II are mechanically position or action of the latch II. An indicator connected by an insulating cross bar 2l.. strip ll has one end supported by the plate It and the other end extended through the base II M the rating of the capacity of the switch.

When the switch is in the closed circuit position as shown in Fig. 6 the latch 33 engages the beveled tip ("of the catch member and is held therebythe spring pressure or bias of the arms I5 and 18 through the cross bar 20 which presses upon the tail 3B of the catch andtends to rotate away from the latch member into the position shown in Fig. '7, thus opening the circuit without affecting the toggle action. To reset the switch it is merely necessary to tilt the finger piece 2| from the position of Fig. 6 ,to the position of Fig. 5 which throws the'catch back into the position shown in Fig. 5.

From the foregoing it will be seen that the switch may be actuated manually under normal circumstances in the same manner as any toggle action switch. ,It will also be seen that under overload conditions the heater unit will cause the thermostatic latch to warp and release the flipper or catch which in turn allows the movable switch members to open the circuit with a snap action even though the operating handle is held in the on position. The catch or flipper has no spring of its own but its movement is caused by the action of the spring arms l5 and I8 above described which is not interfered with by the main spring.

One of the importantynovel features in this present invention is the freely mounted flipper or catch member-which requires no spring of its own and functions as a latching or catch member.

It will be further seen that the normal toggle action is wholly independent of the thermostatic action. The resistance heater unit is detachable and can be readily replaced. Obviously the same mechanism may be employed for different capacities by the simple expedient of properly designing the thermostatic latch and the heater unit.

I claim:

1. In a toggle action thermostatic switch, an insulating support, a metal frame carried thereby and having a toggle action device, a freely piv-' oted catch carried by one part of the toggle action device and a thermostatic latch coacting with the catch. I

2. In a toggle action switch, a spring switch member, a toggle action device including a catch,

- carried by one part' of the device and coacting with the spring switch member and a thermostatic latch coacting with said catch.

3. In a toggle action thermostatic switch, a metallic frame, a toggle member hinged at one end of the frame, aflnger piece hinged to the toggle member, a spring for biasing the toggle member, a catch loosely hinged to the toggle member, a spring pressed switch member moved in one direction by the catch and a thermostatic latch coacting with said catch to permit the normal opening and closing of the switch but adapted to release the catch and spring pressed switch member in case of an overload.

4. In a thermostatic switch, a toggle action device, a freely pivoted catch carried by one part of the toggle action device and a thermostatic latch coacting with the catch and a spring pressed 20,649 and exposed at the front with a mark indicating 5. In a toggle action switch, a spring switch arm, a toggle action device including a catch pivoted to one part of the device and coacting with the spring switch arm and a resilient thermostatic latch coacting with said catch.

6. In a toggle action thermostatic switch, a metallic frame, a toggle member hinged at one end to the frame, a finger piece connected to the toggle member, a spring for biasing the toggle member, a catch hinged to the toggle member, a spring pressed switch member moved in one direction by the catch and a resilient thermostatic latch coacting with said catch and adapted to release 'the catch and spring pressed switch member in case of an overload.

7. An electric switch including a pivoted operating lever, a pivoted toggle member hinged to' the operating lever, a catch member hinged to the toggle member, a spring pressed switch mem ber coacting with the catch member anda thermostatic latch normally interposed in the path of the catch member.

8. A snap switch including a stationary contact, a movable switch member for coacting therewith and normally biased to the off position, operating mechanism coacting with the. movable switch member and including a finger lever, an oscillating member connected to the finger lever, means pivotally carried by the oscillating member and free to move on occasion of. an overload,

a thermal element holding said means under normal circuit conditions and a throwing spring coacting withthe oscillating member ,for actuating the same so as to open and close the circuit with a snap action when said finger lever is manually operated and so as to permit opening the circuit with a snap action when the thermal element releases said means. a

9. In a snap switch, an insulating support having a passage extending from front to rear'of said support, a stationary contact and a cooperating movable contact' carried 'by said support, said movable contact being biased to an open circuit position,

and having ears projecting into said passage, a

.flnger lever pivotally carried by said ears, an oscillating member pivotally carried by and reopen and close the circuit and so that the movable contact will automatically open the circuit upon an overload in the circuit.

10. In a snap, switch, a stationary contact, a movable switch element cooperating therewith and normally biased in an off position, an oscillating member; a finger lever connected to the oscillating member, a throwing spring interposed between said finger lever and said oscillating member, a flipper member mounted on said oscillating member and coacting with the movable switch element .to operate'the same when the finger lever is "i'nanually operated to open and close the circuitpand av'thermally actuated member holding said flipper, member under normal load circuit conditions and adapted to release a thermally actuated element carried by the support, a frame secured to said support with and normally biased to the open circuit po-.

sition, an operating unit including a finger lever, an oscillatingmember connected thereto, a combined cam and catch member pivotally mounted on and carried by said oscillating member and serving to hold the movable contact in the closed circuit position and tree to move on occurrence of an overload in the circuit, a thermally actuated element holding said combined cam and catch member under normal circuit conditions and adapted to be released uponan overload condition and a throwing spring interposed between said flnger lever and said oscillating member for opening said switch with a snap action during normal circuit conditions and said biased movable contact opening the switch with a snap action on an overload condition.

12. A snap switch having stationary contacts, a' movable contact cooperating therewith, actuating mechanism includingan operating handle member, an oscillating member and a throwing spring connecting the last two said members,

means responsive to an overload in the circuit," controlling means for the movable contact car-' ried by said oscillating member and acting as a unit with said oscillatingmember when latched to the overload-responsive means andbecoming inoperative upon occurrence of an overload, said actuating mechanism being constructed to reset the controlling means by manually moving said operating handle to the oil position. 1

I 13. In a snap switch, an operating member, an oscillating member and a spring member, said oscillating member being movable with a snap action from open to closed switch position under the influence oi the spring governed by said operating member, a movable contact arm biased by its own resilience to the open circuit position, a thermostatic latch member, a flipper member carried by said oscillating member adapted when engaged by said thermostatic latch to cause said movable contact arm to be under control of said operating member and when said thermostatic latch. is disengaged from said flipper member said movable contact is released iromcontrol of said operating memben. a

14. In a thermostatic switch, an oscillating member carrying'a pivoted flipper member, movable switch members biased to open circuit position, a thermostatic latch normally engaging said flipper member, said flipper member adapted to hold said movable switch members in closed position when said oscillating member is in closed position and said flipper member is engaged by said thermostatic latch, and said flipper member being adapted to release said movable switch members when said oscillating member moves to the open position or said flipper member is released by the thermostatic latch.

15. In an overload protective switch, a movable switch member biased to open circuit position, an over-center spring device including a flipper carried by one part of thedevice and having a catch portion coacting with the movable switch member and an overload latch coactlng with said catch portion and adapted when released upon predetermined conditions to permit movement oi the movable switch member and manually operable means for re-engaging said catch portion and said overload latch when the overcenter spring device is moved to open circuit position.

16. In an overload protective switch an operating member and an oscillating member, an overce'nter spring connecting said operating member to said oscillating member, a flipper member carried by said oscillating member and movable therewith, a thermostatic latch engaging said flipper member to cause its movement to be dependent upon the movement of said oscillating member and releasing said flipper member to permit it to move independently of said oscillating member, a movablecontact biased to move to the open circuit position, said contact being under control of said flipper member while the flipper member is engaged by the thermostatic latch but free to move to the open circuit position when said flipper member is released by the thermostatic latch.

17. In a snap switch, ,two pairs oi line terminals, a pair of stationary contacts connected to two of said terminals, flat spring switch members, each having one of itsends connected to one of the other terminals and having its free end biased away from contact with one of the stationary contacts, a cross bar connecting the spring switch members, a pivoted operating handle, a pivoted toggle link, an over-the-center spring operably connected with said operating handle and said toggie link and a cam member carried by said toggle link, said handle, spring and toggle member being operable to force said cam into engagement with said cross bar to-Iorce said spring switch members into the on position with a snap action when the handle/ is moved to the on position and'to move the cam away so as to allow the spring switch members to snap into the position through their own' resiliency when the handle is moved-to tion.

18. In a snap, switch, a pair of line terminals, a stationary contact connected to one or said terminals, a resiliently movable switch member i! posihaving one of its ends connected to the other terminal and having a free end normally biased away from electrical contact withsaid stationary contact, a pivoted operating handle, a pivoted toggle link connected to said handle,v an over-the-center spring having operable connection with said handle and said toggle link, a cam member carried by said toggle link and insulating means between said switch member and said cam, the said handle and said spring being adapted to move the toggle link so that the cam member will force the resilient switch member into the on position with a snap action when the handle is moved into' the on position and so that the cam member will be moved away to allow the switch member to snap into the oil! position by its own resiliency when the handle is moved into the of! position.

19. In an automatic trip switch, a stationary contact, a movable contact, a'member for controlling movement of the movable contact, a

pivoted lever, said controlling member being supported by said lever. but movable relative thereto, a releasable support for said controlling member, said lever, controlling member, and

\ contact thereby being movable in unison to produce selectively a normal closed and normal open position of the switch when said releasable support is in supporting position, and current responsive means vfor causing movement or the movable contact and controlling member moving releasable support to withdraw said support from said controlling member, and resilient means for moving said movable contact and controlling member independently of said lever to open the switch when said releasable support is released.

'20. In an automatic trip switch, a stationary contact, a movable contact constantly biased toward open position, a member for controlling movement or the movable contact, a pivoted lever, said controlling member being pivotally supported by said lever, a releasable support for said controlling member, said lever, controlling member, and contact thereby being movable in unison to produce selectively normal closed and normal open positions 0,! the'switch when said releasable support is in supporting position, and current responsive means for causing movement of the releasable support to withdraw said support from said controlling member, said biased independently of said lever to open the switch when said releasable support is released.

21. In an automatictrip switch, a stationary contact, a movable contact, resilient means bias-- means for moving said, lever, said lever, control-' ling member, and contact thereby being movable in unison to produce selectively a normal. closed and normal open position of the switch when said releasable support is in supporting position,'

and current responsive means for causing movement of the releasable support to withdraw said support from said controlling member, said resilient biasing means thereupon moving said movable contact and pivotally moving said controlling member independently oi said lever to open the switch when said releasable support is released.

HERMAN J. HAIVIMERLY; 

